Compensating for temperature effects in a health monitoring system

Abstract

A method is present for monitoring a structure. A plurality of modes is identified for a first response for the structure at a first temperature. Each mode in the plurality of modes is adjusted from the first temperature to the second temperature to form a plurality of temperature adjusted modes. A temperature adjusted response is formed from the plurality of temperature adjusted modes in which the temperature adjusted response is adjusted to a second temperature from the first temperature. The temperature adjusted response is compared to a second response to evaluate the changes in the structure between the two sets of measurements.

What is claimed is: 
     
       1. A method for monitoring a structure, the method comprising:
 identifying a plurality of modes for a first response for the structure at a first temperature; 
 adjusting each mode in the plurality of modes from the first temperature to a second temperature to form a plurality of temperature adjusted modes; 
 forming a temperature adjusted response from the plurality of temperature adjusted modes in which the temperature adjusted response is adjusted to the second temperature from the first temperature; and 
 comparing the temperature adjusted response to a second response obtained at the second temperature. 
 
     
     
       2. The method of  claim 1  further comprising:
 sending a signal into the structure, wherein the signal causes the first response. 
 
     
     
       3. The method of  claim 2 , wherein sending step comprises:
 sending the signal into the structure using a transmitter. 
 
     
     
       4. The method of  claim 3  further comprising:
 receiving the first response using a sensor. 
 
     
     
       5. The method of  claim 4 , wherein the transmitter and the sensor are a transducer. 
     
     
       6. The method of  claim 1  further comprising:
 determining whether a change has occurred in the structure from comparing the temperature adjusted response to the second response obtained at the second temperature. 
 
     
     
       7. The method of  claim 1 , wherein the adjusting step comprises:
 adjusting the each mode in the plurality of modes from the first temperature to the second temperature using a set of transforms to form the plurality of temperature adjusted modes. 
 
     
     
       8. The method of  claim 6  further comprising:
 responsive to a determination that the change has occurred in the structure, mapping the change. 
 
     
     
       9. The method of  claim 1 , wherein the structure is selected from one of an aircraft, a building, a dam, a submarine, a spacecraft, a ship, a truck, a tank, a bridge, and a wall. 
     
     
       10. An apparatus comprising:
 a structure having a set of components; 
 a set of transmitters physically associated with the set of components, wherein the set of transmitters is capable of sending signals into the set of components; 
 a set of sensors physically associated with the set of components, wherein the set of sensors is capable of detecting a response to the signals; and 
 a data processing system in communication with the set of transmitters and the set of sensors, wherein the data processing system is capable of identifying a plurality of modes for a first response for the structure at a first temperature; adjusting each mode in the plurality of modes from the first temperature to a second temperature to form a plurality of temperature adjusted modes; forming a temperature adjusted response from the plurality of temperature adjusted modes in which the temperature adjusted response is adjusted to the second temperature from the first temperature; and comparing the temperature adjusted response to a second response obtained at the second temperature. 
 
     
     
       11. The apparatus of  claim 10 , wherein the data processing system is capable of causing the set of transmitters to send a signal into the structure, wherein the signal causes the first response and receives the first response using the set of sensors. 
     
     
       12. The apparatus of  claim 10 , wherein the data processing system is configured to determine whether a change has occurred in the structure from comparing the temperature adjusted response to the second response obtained at the second temperature. 
     
     
       13. The apparatus of  claim 12 , wherein the data processing system is configured to map the change in response to a determination that the change has occurred in the structure. 
     
     
       14. The apparatus of  claim 10 , wherein the data processing system is configured to adjust the each mode in the plurality of modes from the first temperature to the second temperature using a set of transforms. 
     
     
       15. The apparatus of  claim 10 , wherein the set of transmitters and the set of sensors are a set of transducers. 
     
     
       16. The apparatus of  claim 10 , wherein a transmitter and a sensor in the set of transmitters and the set of sensors are comprised of a single device that transmits a signal in a first mode and then changes to a second mode to detect a response to the signal. 
     
     
       17. A computer program product comprising:
 a non-transitory computer recordable storage media; 
 program code on the computer readable storage media for identifying a plurality of modes for a first response for a structure at a first temperature; 
 program code on the computer readable storage media for adjusting each mode in the plurality of modes from the first temperature to a second temperature to form a plurality of temperature adjusted modes; 
 program code on the computer readable storage media for forming a temperature adjusted response from the plurality of temperature adjusted modes in which the temperature adjusted response is adjusted to the second temperature from the first temperature; and 
 program code on the computer readable storage media for comparing the temperature adjusted response to a second response obtained at the second temperature. 
 
     
     
       18. The computer program product of  claim 17  further comprising:
 program code on the computer readable storage media for sending a signal into the structure using a transmitter, wherein the signal causes the first response; and 
 program code for receiving the first response using a sensor. 
 
     
     
       19. The computer program product of  claim 17  further comprising:
 program code on the computer readable storage media for determining whether a change has occurred in the structure from comparing the temperature adjusted response to the second response obtained at the second temperature. 
 
     
     
       20. The computer program product of  claim 17  further comprising:
 program code on the computer readable storage media for receiving the first response using a sensor. 
 
     
     
       21. The method of  claim 1  wherein a mode comprises a component of a waveform. 
     
     
       22. The apparatus of  claim 10  wherein a mode comprises a component of a waveform. 
     
     
       23. The computer program product of  claim 17  wherein a mode comprises a component of a waveform.